Your chainsaw should cut straight, and if it’s pulling left or right, then something is wrong.

This is a pretty common problem for chainsaw users, and I’ve seen a wide range of explanations in online forums and discussion boards. Unfortunately some of the suggestions out there are just plain wrong. 

I was talking with my Dad today (a forester with 30+ years of experience), and he had adamant reactions to some of the online comments. So, in this post, we’re going to set the record straight.

If your chainsaw is not cutting straight, this is due to one of two things:

1. Your chain is dull on one side
2. The edges of your bar are uneven

There are a several ways these two things could happen. We’ll look at each one individually below, then we’ll talk about solving the problem. ​

Note: If you’re wondering if it could be from a bend or bump on your chainsaw bar, that’s not it. Think about it, you can’t cut a log in a curved moon shape, and if there was a significant bend it would probably throw the chain. If you’ve got a pull in one direction, it’s one of the 2 things above.

Now let’s get to the problem solving!

1. Your chain is dull on one side

This is probably the most common reason that your chainsaw could be pulling in one direction. Both new and experienced chainsaw users could encounter this problem. 

A. Causes of an uneven chain

Imagine this, you’re chunking up a fallen tree, and when you get through the log you hit a patch of dirt. I’ve done it, it happens. 

When you hit dirt, or grind into a rock, that can take a big toll on your chain. 

I know what you’re thinking, “duh!”. If you hit a rock with your chain, it’s going to damage it. Pretty obvious.

But, what you might not have thought about, is the fact that hitting a rock will wear down one side of your chain more than the other side. Think about it, one side will be taking the bulk of the damage. 

As a result, if you’re trying to figure out why your chainsaw won’t cut straight, ask yourself if you’ve recently ground into something. If you have, then your problem is almost definitely a chain that is duller on one side.

There’s another reason you might have an uneven chain, and that’s lopsided sharpening. If you’re inexperienced and have been sharpening your chain with a manual file, then it’s possible that you’ve ground one side harder than the other. The result is a “crooked” cut.

So to summarize, if you have an uneven chain then it was probably caused by:

1. Hitting dirt, a rock, etc.
2. Sharpening your chain unevenly

If you don’t think either of these are your problem, then skip down to section 2 below. Otherwise, let’s dive-into fixing the chain.

B. How to fix an uneven chain

If it’s a minor case, then you might be able to fix it by sharpening the chain with a file until it’s even. 

Your chain will have links on both sides of the chain. Each guide link AND each cutter link will have a small line on it. See image below for an example of what this line looks like. Want to learn more about chain anatomy? Check out this article.

The purpose of these lines is to show the point at which a link can no longer be sharpened (e.g. the maximum amount of metal that can be removed).

For our purposes here, the line is also helpful as a comparison tool. It provides a consistent benchmark, that you can use to compare how far links on each side are ground down.

If there are huge differences, then you may want to have your chain professionally sharpened at a local saw shop. If there are chips or breaks in the chain, then it will need to be replaced. 

C. How to prevent an uneven chain

Okay, once your chain is fixed, sharpened or replaced, you’re going to want to keep it that way. 

And the best way to do that, is by simply avoiding the causes of chain damage outlined above. 

In other words, take extra precautions not to hit dirt or rocks with your chain. Sure, it could still happen from time to time, but most of us could be a bit more cautious of this. 

If you’re cutting wood on the ground, try to stop ~6 inches above the ground, and roll the log over to finish the cut from the other side. If that’s not feasible, and the log can’t be moved, try to keep your chainsaw level to the ground to prevent/eliminate contact with the ground.

The other problem we’ve talked about, is uneven sharpening. To prevent this, use a file with a guide, like this one (FYI – I get a commission on this if you buy one). Using a file with a guide like this, can help keep things even.

You can also practice applying equal pressure when you sharpen from each end. This is a skill, and it can take some time to get good at it.

2. The edges of your bar are uneven

As I mentioned earlier, the chain is most likely the root cause of your problem, but if that’s not it, then it could also be your chainsaw bar.

A. Causes of an uneven bar

It’s almost inevitable for the edges of a chainsaw bar to wear unevenly. The metal-to-metal friction between the bar and chain will rub off metal gradually. The side that loses material most quickly can depend on your dominant hand, the direction a tree is leaning, and other factors.

A best practice used by experienced chainsaw users, is to flip the bar regularly, to balance things out. If you’re not doing this currently, then it’s likely that one edge of your bar will get shorter than the other (on either side of the chain groove). 

B. How to fix an uneven bar

You can fix an uneven bar, by filing the edges until they are level. See below to see what I mean:

What you have to do is scrape the edges of your bar with the file, while holding it as evenly as possible. You should do this each time you perform maintenance on your chainsaw.

The file used in the image above is Pferd’s edge sharpener tool. You can find one here (FYI – I get a commission on these).

Using a filing tool like this is better for your bar, and cheaper in the long run, compared to having someone grind the edge off at a saw shop. 

C. How to prevent an uneven bar

A good rule of thumb, is to flip your chainsaw bar every time you fill up with fuel. 

On most chainsaws, you can do this by…

Removing the front panel.

Lifting the bar off the chainsaw.

Then you remove the chain.

Finally, you flip the bar over, and put everything back together.

Bonus: keeping your chainsaw bar clean

The chainsaw bar groove gets oil, sawdust, and dirt caught in it. As you can imagine, it’ll run better without all that junk in there.

Use a gauge tool, and slide it along the bar groove, to clean it out.

Also, you won’t want to miss the oil hole. 

Use your gauge tool to clean the oil hole on both sides of the bar, to keep your chain running smoothly. This can also prevent smoking and overheating.

Here’s where you can find it:

Wrap-up

That’s it! 

I hope you’ve found this article helpful, and that you came away with some answers for your specific chainsaw challenge.

If you did find something useful in this article, please share our website with someone else who might be interested in it. We always love to hear from people who have benefited from our blog, and we love reaching new people, so help us get the word out!

Now go do something awesome.